Bin storing a hot asphalt mix



NOV. 14, J. D. BROCK BIN STORING A HOT ASPHALT MIX Filed Sept. 26, 1966 M, w. m Mw N Z NOW /o m s 59 M United States Patent 3,352,354 BIN STORING A HOT ASPHALT MIX James D. Brock, Chattanooga, Tenn., assignor to Industrial Boiler Company, Inc., Chattanooga, Tenn., a corporation of Tennessee Filed Sept. 26, 1966, Ser. No. 581,970 Claims. (Cl. 165-469) ABSTRACT THE DISCLOSURE What is disclosed herein is a bin for storing a hot mix such as a hot asphalt mix which includes a storage chamber in which the hot asphalt mix is stored, a housing and a first spiral conveyor positioned above the storage chamber for substantially uniformly distributing a hot asphalt mix along the length of the storage chamber through apertures of progressively increasing size in the housing, and a conveyor chamber and a second spiral conveyor positioned below the storage chamber for conveying substantially uniform amounts of a hot asphalt mix'from along the length of the storage chamber to a discharge opening. In addition, the bin is disclosed as including a heating means for maintaining the temperature of a hot asphalt mix in the storage chamber. The bin disclosed provides a bin having a large storage capacity without requiring excessive height and Without horizontal movement and separation by size of aggregate.

This invention relates to a vessel for aggregate and more particularly to a bin for a hot mix including aggregate such as asphalt paving mix.

There is a frequent requirement in the paving art for a bin to be used in the temporary storage of asphalt paving mixes which are mixtures of asphalt and various sizes of aggregate. With respect to asphalt paving mixes, this requirement exists because of the difficulty in coordinating the production of an asphalt paving mix by an asphalt plant with the use of the asphalt paving mix at various construction sites remote from the asphalt plant. As a result of this difficulty and in the absence of a bin, trucks are frequently kept waiting while the asphalt plant produces suflicient asphalt paving mix to load the trucks and it is frequently necessary to discontinue the operation of an asphalt plant because of the absence of trucks to receive the asphalt paving mix as it is produced.

A bin alleviates this difiiculty by receiving and storing the asphalt paving mix as it is produced by the asphalt plant so as to reduce the coordination required between the production of asphalt paving mix by an asphalt plant and the use of the asphalt paving mix at construction sites. This is because a bin permits the asphalt paving mix to be produced in the absence of trucks and permits trucks to be loaded with the asphalt paving mix produced in their absence as well as during their loading.

However, a difiiculty with prior art bins when used to meet this and similar requirements is that they have been limited in practical size because of the tendency of the upper surface of a hot mix such as an asphalt paving mix within these prior art bins to form hills with sloping sides as the mix is fed to and removed from the bins. Such a hill causes horizontal movement by gravity of the aggregate in an asphalt paving mix within a bin. The extent of this horizontal movement is in proportion to the size of the aggregate and results in the separation of aggregate by size.

When the horizontal dimensions of prior art bins have been too large, the horizontal movement of the larger aggregate in an asphalt paving mix relative to the smaller aggregate has been so great that the resulting separation of aggregate by size has caused a lack of uniformity in ice the asphalt paving mix which is unacceptable for many uses of asphalt paving mix. Thus, the horizontal dimensions of prior art bins have been limited to those which would limit horizontal movement of aggregate and the separation of aggregate by size and large capacity prior art bins have been possible only by using great vertical heights for the bins or by using a plurality of separate chambers arranged in the bins to limit horizontal movement of aggregate. However, bins of great vertical height are impractical to build and use in many applications and a plurality of chambers within a bin are impractical both because of the increased cost and because of difiiculties encountered in loading trucks from a plurality of chambers.

The invention disclosed herein overcomes these and other difiiculties encountered with prior art bins. This is because the invention provides a bin with a single chamber for the storage of a hot mix such as an asphalt paving mix which has a lengthwise dimension which may be substantially unlimited in length. As a result, a bin of substantially greater capacity than has been possible with prior art bins is provided without excessive vertical height and without using a plurality of chambers within the bin.

This improvement in bins is achieved by a bin which includes distributing means for uniformly distributing an asphalt paving mix along the length of a chamber and conveying means for uniformly conveying the asphalt paving mix along the length of the chamber to a discharge aperture. Although the asphalt paving mix will form a ridge of substantially uniform height along the length of the chamber, the widthwise dimension of the chamber transverse to its lengthwise dimension is selected to provide a width which is sufiiciently short to limit horizontal movement of aggregate and the separation of the aggregate by size to acceptable limits.

Thus, unlike prior art bins which could provide large storage capacity only by extending their vertical heights or by using a plurality of separate chambers within the bin, the distributing means and the conveying means of the bin disclosed herein serve to provide a bin having a capacity which may be increased by increasing both the vertical height and the length of the bin. This avoids the difficulties encountered in prior art bins with excessive vertical heights or with a plurality of separate chambers within the bin. Moreover, the invention also provides a bin with an improved heating means for maintaining the temperature of the large amount of hot asphalt mix which it is possible to store within the bin.

It is because of this heating means and because of the capacities which are possible with the bin disclosed herein, that the bin disclosed herein not only provides an improved bin for storing hot asphalt mix as it is produced by an asphalt plant, but also provides a bin which is suitable for storing a large portion of the hot asphalt mix requirements for a construction site so that the bin in effect becomes a satellite plant not requiring the relatively expensive equipment associated with an actual asphalt plant. Those skilled in the art will also recognize that many other advantageous uses may be made of a bin embodying the invention in view of the storage capacities which are practical.

These and other features and advantages of the invention will be more clearly understood from the following detailed description and the accompanying drawing in which like characters of reference designate corresponding parts throughout and in which:

The figure is a sectional view of a bin embodying the invention disclosed herein.

This figure and the following detailed description disclose a specific embodiment of the invention, but the invention is not limited to the details disclosed since it may be embodied in other equivalent forms.

W for defining a storage chamber 10, a distributing means D for uniformly distributing a hot asphalt mix along the length of the storage chamber 10, and a conveying means C for uniformly conveying a hot asphalt mix within the storage chamber to a discharge opening 35. In that embodiment of the invention disclosed, the wall means W includes an inner wall 12 and an outer wall 13 parallel to and spaced from the inner wall 12 so as to define a heating cavity 14 which extends around the upper portion of the storage chamber 10. The vertically extending heating cavity 14 is closed at its upper end by a cover plate 15 which also serves to provide a cover for the storage chamber 10. At its lower end, the heating cavity 14 is closed by a flange 16 which extends outwardly from the inner wall 12 to join the outer wall 13.

Within the heating cavity 14 and aiding to maintain the inner wall 12 in spaced relationship with the outer wall 13 are a plurality of downwardly. extending vertical spacer members 17 alternating with a plurality of upwardly extending vertical spacer members 18. Each vertical spacer member 17 or 18 extends between the inner wall 12 and the outer wall 13 and the downwardly extending vertical spacer members 17 are integral with the cover plate 15 and spaced from the flange 16 while the upwardly extending vertical spacer members 18 are integral with the flange 16 and spaced from the cover plate 15. Thus, the vertical spacer members 17 and 18, the walls 12 and 13, the cover plate 15, and the flange 16 serve to define a channel 19 which surrounds the upper portion of the storage chamber 10 and which alternately extends upwardly and downwardly between the inner wall 12 and the outer wall 13.

In addition to the vertical spacer members 17 and 18, a divider member 20 also extends between the inner wall 12 and the outer wall 13. However, unlike the vertical spacer members 17 and 18, the divider member 20 extends be tween the cover plate Y15 and the flange 16 so as to make the channel 19 discontinuous. Thus, it will be understood that if a heating medium such as hot oil is introduced into the channel 19 through an inlet pipe .21 on one side of the divider member 20 and is removed from the channel 19 on the opposite side of the divider member 20 through an outlet pipe 22, the heating medium will flow through the channel 19 in a path which is alternately upwardly and downwardly within the heating cavity 14.

This flow of a heating medium in the channel 19 will serve to maintain the temperature of a hot mix such as a hot asphalt mix within the storage chamber 10 for extended periods of time. Moreover, it will be understood that a variety of devices (not shown) for providing a heating medium may be operatively connected to the pipes 21 and 22 and that regardless of the device (not shown) used, the flow of a heating medium in the alternately up-- wardly and downwardly path defined by the channel 19 provides a heating means H for insuring a substantially even vertical distribution of the heat provided by the heating medium so that zones or layers of diflferent temperature are not formed within the storage chamber 10.

Carried by and partially extending through the cover plate 15 is the distributing means D which in that embodiment of the invention disclosed includes a conveyor housing 23 and a spiral conveyor 24 rotatably positioned within the conveyor housing 23.The spiral conveyor 24 is rotated by a conventional motor 25 positioned on the conveyor housing 23 and which drives the spiral conveyor 24 through a plurality of belts 26 and pulleys 27. That portion of the conveyor housing 23 which extends through the cover plate 15 hasa contour generally corresponding to the contour of the spiral conveyor 24 and has a plurality of'apertures 28 distributed along its length. At one end, the conveyor housing 23 is continuous with a receiving chute 29 by which hot asphalt mix is received into the conveyor housing 23 from a source of hot asphalt mix (not shown).

It will now be understood that rotation of the spiral conveyor 24 in that direction indicated by the arrow A in the drawing causes hot asphalt mix received within the conveyor housing 23 through the receiving chute 29 to be moved along the length of the conveyor housing 23 by the spiral conveyor 24. As the hot asphalt mix moves along a path extending the length of the conveyor housing 23,'the hot asphalt mix falls from the conveyor housing 23 through the apertures 28.

However, the sizes of the apertures 28 are selected so that only a portion of the total amount of hot asphalt mix moved by the spiral conveyor 24 will fall through each aperture 28. As a result and with proper selection of aperture 28 size, substantially equal portions of the total hot asphalt mix received in the conveyor housing 23 through the receiving chute 29 fall from all apertures 28 along the length of the conveyor housing 23. It will be understood that a similar result will be obtained by a single aperture 28 extending and varying in width along the length of the conveyor housing 23 or by other arrangements of one or more apertures 28 which also serve to provide an aperture means for allowing only some of the hot asphalt mix moved by the spiral conveyor 24 along the conveyor housing 23 to fall into the storage chamber 10 at a particular point along the conveyor housing 23. Regardless of the aperture 28 arrangement, the distributing means D provides a means for the uniform distribution of hot asphalt mix to the storage chamber 10 along the length of the conveyor housing 23.

The lower portion of the storage chamber 10 is formed by walls 30 continuous with the inner wall 12 and inclined inwardly and downwardly to be also continuous with a conveyor chamber 31 in which a spiral conveyor 32 is rotatably positioned. It will be understood that the walls 30 serve to guide hot asphalt mix into the conveyor chamber 31 where rotation of the spiral conveyor 32 through belts 33 by a motor 34 causes the hot asphalt mix to be moved along the conveyor chamber 31.

In that embodiment of the invention disclosed, the

conveyor chamber 31 has a discharge opening 35 in its lower side and above both the discharge opening 35 and the spiral conveyor 32 is a wedge shaped batlle 36. The bafiile 36 prevents hot asphalt mix in the storage chamber 10 from passing downwardly by gravity through the spiral the right of the discharge zone 37. Moreover, the thread 38 is arranged on both sides of the discharge zone 37 so that with rotation of the spiral conveyor 32 in the direction indicated by the arrow 39 in the drawing, the hot asphalt mix is moved along a path to the right by that portion of the spiral conveyor 32 to the left of the dischargezone 37 and is moved along a path to the left by that portion of the spiral conveyor 32 to the right of the discharge zone 37.

In addition, it will be noted from the drawing that both to right and left of the dischargezone 37, the spiral conveyor 32 progressively decreases indiameter from the discharge zone 37 toward the ends of the spiral conveyor 32. It will be understood that this progressive change in diameter of the spiral conveyor 32 results in the spiral conveyor 32 engaging substantially equal amounts of hot asphalt mix in the storage chamber 10 between the ends of spiral conveyor 32 and the discharge zone 37 and that the spiral conveyor 32 serves as a conveying means for conveying substantially equal amounts of hot asphalt mix from all along the length of the conveyor chamber 31.

Thus, with the conveyor housing 23 and the conveyor chamber 31 extending parallel to and along a horizontal axis such as the lengthwise dimension of the storage chamber and the bin B, the lengthwise dimension of the bin B is limited only by the length selected for the spiral conveyors 24 and 32. This is because the uniform distribution of hot asphalt mix along a first path in the storage chamber 10 by the distributing means D and the uniform conveying of hot asphalt mix along a plurality of second paths substantially p-arallel to the first path in the storage chamber 10 by the conveying means C serve to insure that hot asphalt mix within the storage chamber 10 remains of substantially uniform height within the storage chamber 10 along the lengthwise dimension of the storage chamber 10 and the bin B. As a result, the lengthwise dimension of the bin cannot cause the forming of hills of hot asphalt mix within the storage chamber 10 which would result in substantial horizontal movement of aggregate and unacceptable segregation of aggregate by sizes.

The combination of the substantially unlimited lengthwise dimension for a bin B which is provided by the invention disclosed herein with a widthwise dimension selected to limit any hill of hot asphalt mix formed wtihin the storage chamber 10 by an uneven distribution for conveying of hot asphalt mix along the widthwise dimension provides a bin B which may be of great capacity without an impractical vertical height and with but a single storage chamber 13 while at the same time avoiding the undesirable horizontal movement and segregation of aggregate which would be present in single-chamber prior art bins having similar dimensions. Moreover, because of the large capacities which may be provided by a bin 13 as a result of the distributing means D and the conveying means C and because of the means for maintaining a hot asphalt mix within the storage chamber 10 at a desired temperature which is provided by the heating means H, the bin B is ideally suited not only to receive hot asphalt mix directly from an asphalt plant, but is also ideally suited for the storage at a construction site of large quantitles of hot asphalt mix brought to the bin B by trucks for subsequent use as needed at the construction site.

Regardless of the manner in which the bin B is used, the bin B provides convenient means for receiving and storing hot asphalt mix for subsequent discharge and use. Where the hot asphalt mix is to be discharged from the bin B into a truck or a plurality of trucks, this is conveniently provided for by supporting the bin B with a plurality of base members 50 which serve to raise the bin B by that amount necessary for a truck or other vehicle to be driven beneath the bin B and the discharge opening 35 for the discharge of the hot asphalt mix from the bin B directly into the truck. However, it should be understood that the bin B may be used to discharge a hot mix such as hot asphalt mix onto a conveyor system (not shown) or in any of a variety of other applications and that regardless of the application in which the bin B is used, it provides a bin of great capacity in which the segregation of aggregate by size is substantially eliminated and in which the temperature of the hot mix may be maintained over prolonged periods of time.

It will be obvious to those skilled in the art that many variations may be made in the embodiments chosen for the purpose of illustrating the present invention without departing from the scope thereof as defined by the appended claims.

What is claimed as invention is:

1. In a bin storing a hot asphalt mix; wall means for defining a chamber for receiving a hot asphalt mix in said chamber as said hot asphalt mix is distributed along a first path by a distributing means; said distributing means including a housing having a plurality of apertures of progressively increasing size positioned in sequence along said first path, and said distributing means including conveyor means for conveying said hot asphalt mix along said housing past said plurality of apertures; and conveying means for conveying along a plurality of second paths substantially parallel to said first path amounts of said hot asphalt mix which progressively increase along each of said second paths toward a discharge opening; said conveying means including a spiral conveyor which progressively increases in diameter along each of said second paths.

2. The bin of claim 1 including bafile means for restricting movement of said hot asphalt mix toward said discharge opening to that movement provided by said conveying means.

3. The bin of claim 1 in which said wall means includes an inner wall and an outer wall spaced from said inner wall by a plurality of substantially vertically extending spacer members.

4. The bin of claim 3in which said spacer members define a continuous channel and including means for circulating a heating medium through said channel.

5. The bin of claim 3 in which said spacer members are positioned to define a channel extending alternately upwardly and downwardly between said inner wall and said outer wall.

6. The bin of claim 1 in which said conveyor means is a spiral conveyor rotatably positioned within said housing.

7. The bin of claim 1 in which said chamber is elongated along a horizontal axis and in which said first path is substantially parallel to said horizontal axis.

8. The bin of claim 1 including a receiving chute continuous with said housing at one end of said housing and whereby a hot asphalt mix is received in said housing.

9. The bin of claim 1 in which said chamber is a storage chamber and including a conveyor chamber which is continuous with said storage chamber at its lower end and in which said spiral conveyor is positioned.

10. The bin of claim 2 in which said bafile means is positioned above said discharge opening and said spiral conveyor to define a discharge zone and in which said plurality of second paths terminate in said discharge zone.

References Cited UNITED STATES PATENTS 1,704,731 3/1929 Eggert 198-214 2,190,724 2/1940 McBride 217-17 X 2,209,561 7/1940 Curtis -169 X 2,772,784 12/1956 Cyphers 165-169 X 2,961,126 11/1960 Craig 198-213 X 2,969,156 1/1961 Miller et a1. 198-214 X 3,037,611 6/1962 Majorowicz 198-213 X 3,134,478 5/1964 Haen et a1 198-213 X 3,248,093 4/1966 Demaison 259-151 FOREIGN PATENTS 803,891 11/1958 Great Britain.

ROBERT A. OLEARY, Primary Examiner. A. W. DAVIS, Assistant Examiner. 

1. IN A BIN STORING A HOT ASPHALT MIX; WALL MEANS FOR DEFINING A CHAMBER FOR RECEIVING A HOT ASPHALT MIX IN SAID CHAMBER AS SAID HOT ASPHALT MIX IS DISTRIBUTED ALONG A FIRST PATH BY A DISTRIBUTING MEANS; SAID DISTRIBUTING MEANS INCLUDING A HOUSING HAVING A PLURALITY OF APERTURES OF PROGRESSIVELY INCREASING SIZE POSITIONED IN SEQUENCE ALONG SAID FIRST PATH, AND SAID DISTRIBUTING MEANS INCLUDING CONVEYOR MEANS FOR CONVEYING SAID HOT ASPHALT MIX ALONG SAID HOUSING PAST SAID PLURALITY OF APERTURES; AND CONVEYING MEANS FOR CONVEYING ALONG A PLURALITY OF SECOND PATHS SUBSTANTIALLY PARALLEL TO SAID FIRST PATH AMOUNTS OF SAID HOT ASPHALT MIX WHICH PROGRESSIVELY INCREASE ALONG EACH OF SAID SECOND PATHS TOWARD A DISCHARGE OPENING; SAID CONVEYING MEANS INCLUDING A SPIRAL CONVEYOR WHICH PROGRESSIVELY INCREASES IN DIAMETER ALONG EACH OF SAID SECOND PATHS. 